James Glanz
Batavia, Illinois--In a year's harvest of data from the Tevatron particle accelerator at the Fermi National Accelerator Laboratory, a large collaboration of physicists has found hints that quarks may have internal structure. Because quarks are now thought to be fundamental particles, the evidence--a slight excess in the number of sideways jets of debris spurting from proton-antiproton collisions--could challenge the reigning theory of matter. But the Fermilab physicists caution that there are other, less revolutionary, ways to explain the data.